Petrology and geochemistry of acid igneous rocks of northeast Queensland  

Authors / CoAuthors

Sheraton, J.W. | Labonne, B.

Abstract

Acid igneous rocks of northeast Queensland range in age from Precambrian to Permian.The Precambrian to Devonian Forsayth and Robin Hood Granites and the Siluro-Devonian Dumbano Granite and Dido Granodiorite form deep-level intrusions and have generally unfractionated compositions, with relatively high K/Rb and low K/Na ratios. The only significant mineralization associated with them is gold. The Proterozoic Esmeralda Granite and Croydon Volcanics and the extensively mineralized Upper Palaeozoic high-level granitic rocks and their associated volcanics are mostly highly fractionated, with high K2O, Rb, Y, Th, U, and in some cases Li and Be contents, and low K/Rb ratios. The Esmeralda Granite and Croydon Volcanics are considered to have been derived by anatexis of K-rich sialic crustal rocks, but isotopic and chemical data suggest that the Upper Palaeozoic acid magmas originated by anatexis of Rb-poor deep crustal material, possibly caused by rising basaltic or andesitic magmas derived by melting of subducted oceanic crust. Granitic rocks with associated tin mineralization, including the Esmeralda Granite and several of the more fractionated Upper Palaeozoic granitic rocks are enriched in volatile elements such as Li, Be, B and F. Sn contents are significantly higher than those of non-stanniferous granites, but lower than values reported for many Sn-granites elsewhere. No correlation of granite geochemistry with Pb/Zn or Cu mineralization was found. Published for the Bureau of Mineral Resources, Geology and Geophysics by the Australian Government Publishing Service

Product Type

document

eCat Id

66

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Keywords

• GA PublicationBulletin

( Theme )

• petrology

( Theme )

• geochemistry

• AU-QLD

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_External

Publication Date

1978-01-01T00:00:00

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Australian Government Security ClassificationSystem    

Classification - unclassified

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Creative Commons Attribution 4.0 International Licence    

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Use - license

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Purpose

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unknown

Topic Category

geoscientificInformation

Series Information

Bulletin 169

Lineage

Unknown

Parent Information

Extents

[-20.0, -14.0, 141.0, 147.0]

Reference System

Spatial Resolution

Service Information

Associations

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Download the Bulletin (pdf)  

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